I'm looking for a schematic for the above named monitor. My vertical
has compressed down to a thin line across the center of the screen.
Replacing the electrolytic capacitors has not helped.
Searches of the web have been fruitless. One monitor schematic for
the Commodore A2002 was alleged to be similar but when I get down to the
component level they are very different.

--

Rick Jones
Remove the Extra Dot to e-mail me

"Rick Jones" wrote in message
...
I'm looking for a schematic for the above named monitor. My vertical
has compressed down to a thin line across the center of the screen.
Replacing the electrolytic capacitors has not helped.
Searches of the web have been fruitless. One monitor schematic for
the Commodore A2002 was alleged to be similar but when I get down to the
component level they are very different.

--

What use would a schematic be? It should be easy to find the vertical output
IC or transistors on the board, check to see if they're shorted, if they are
then look for an open fusible resistor nearby. Could also be as simple as a
cold solder joint in that area.

James Sweet wrote:

"Rick Jones" wrote in message
...

I'm looking for a schematic for the above named monitor. My vertical
has compressed down to a thin line across the center of the screen.
Replacing the electrolytic capacitors has not helped.
Searches of the web have been fruitless. One monitor schematic for
the Commodore A2002 was alleged to be similar but when I get down to the
component level they are very different.

What use would a schematic be? It should be easy to find the vertical output
IC or transistors on the board, check to see if they're shorted, if they are
then look for an open fusible resistor nearby. Could also be as simple as a
cold solder joint in that area.

I need the schematic to determine exactly which components those are
on the PCBs.

--

Rick Jones
Remove the Extra Dot to e-mail me

On Mon, 15 Nov 2004 21:22:40 -0600, Rick Jones
put finger to keyboard and composed:

I'm looking for a schematic for the above named monitor. My vertical
has compressed down to a thin line across the center of the screen.
Replacing the electrolytic capacitors has not helped.
Searches of the web have been fruitless. One monitor schematic for
the Commodore A2002 was alleged to be similar but when I get down to the
component level they are very different.

Have you tried these URLs?
http://project64.c64.org/hw/peri.html
http://amiga.serveftp.net/schematics.html

I suggest you identify the vertical output IC or transistor pair. It
should be fairly obvious which IC is the right one by following the
yoke connector to the main PCB. These ICs are usually mounted on a
heatsink and are packaged in SIPs. Their supply is most often derived
from a winding on the flyback transformer. There will be a series
rectifier diode and probably a low ohm fusible resistor.

If you still can't find the vertical IC, post some part numbers and
someone will be able to recognise it. You will most probably find that
the datasheet for the IC will contain an application circuit that will
closely match the layout in your monitor.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

Even a "Digital Camera" photo may assist others in helping, please make sure
it is clearly produced.
"Franc Zabkar" wrote in message
...
On Mon, 15 Nov 2004 21:22:40 -0600, Rick Jones
put finger to keyboard and composed:

I'm looking for a schematic for the above named monitor. My vertical
has compressed down to a thin line across the center of the screen.
Replacing the electrolytic capacitors has not helped.
Searches of the web have been fruitless. One monitor schematic for
the Commodore A2002 was alleged to be similar but when I get down to the
component level they are very different.

Have you tried these URLs?
http://project64.c64.org/hw/peri.html
http://amiga.serveftp.net/schematics.html

I suggest you identify the vertical output IC or transistor pair. It
should be fairly obvious which IC is the right one by following the
yoke connector to the main PCB. These ICs are usually mounted on a
heatsink and are packaged in SIPs. Their supply is most often derived
from a winding on the flyback transformer. There will be a series
rectifier diode and probably a low ohm fusible resistor.

If you still can't find the vertical IC, post some part numbers and
someone will be able to recognise it. You will most probably find that
the datasheet for the IC will contain an application circuit that will
closely match the layout in your monitor.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

"Rick Jones" wrote in message
...
James Sweet wrote:

"Rick Jones" wrote in message
...

I'm looking for a schematic for the above named monitor. My vertical
has compressed down to a thin line across the center of the screen.
Replacing the electrolytic capacitors has not helped.
Searches of the web have been fruitless. One monitor schematic for
the Commodore A2002 was alleged to be similar but when I get down to the
component level they are very different.

What use would a schematic be? It should be easy to find the vertical
output
IC or transistors on the board, check to see if they're shorted, if they
are
then look for an open fusible resistor nearby. Could also be as simple
as a
cold solder joint in that area.

I need the schematic to determine exactly which components those are
on the PCBs.


This is not meant to be an insult, but if you can't identify the vertical
output IC or transistors by glancing at the board then you probably should
do some research on CRT display repair before you dig into this one. Very
worst case you could simply follow the traces back from where the vertical
yoke plugs in.

Franc Zabkar wrote:

I suggest you identify the vertical output IC or transistor pair. It
should be fairly obvious which IC is the right one by following the
yoke connector to the main PCB. These ICs are usually mounted on a
heatsink and are packaged in SIPs. Their supply is most often derived
from a winding on the flyback transformer. There will be a series
rectifier diode and probably a low ohm fusible resistor.

If you still can't find the vertical IC, post some part numbers and
someone will be able to recognise it. You will most probably find that
the datasheet for the IC will contain an application circuit that will
closely match the layout in your monitor.

OK, here's some info:

The monitor was manufactured by Toshiba; the name is etched into all
of the PCBs. The main board that lays flat across the bottom has what
appears to be P/N PW5253. This has one IC on it - a 42-pin DIP P/N
TA7644. I have tried to find a datasheet for this IC but no luck.
A second small PCB stands at the back of this and has P/N
PWPW5252-3. This board has all of the connectors for RGB, composite
video, split video and mono audio input for the built-in speaker. There
is one IC on this board, P/N TC4053.
The third board is mounted vertically on the right side (facing the
front of the tube). This PCB is P/N PW5252-1. There are 3 ICs on this
board - P/N HD7407, P/N TC4053 and P/N AN5352.
The 4th board in the system is the yoke board, which I guess we're
all pretty sure is no concern with this particular problem. Also, the 3
digital chips - 7407 and 4053 - would not seem to be of concern.
Research on the AN5352 IC showed it to be a character generator, which
seems odd for a monitor. This unit has no capabilities to function as a
terminal AFAIK.
That leaves the TA7644, which I can find no detailed information on,
just general data that it's a monitor controller IC. Either the vertical
circuit is a part of this 42-pin chip or it's all generated discretely.

--

Rick Jones
Remove the Extra Dot to e-mail me

On Wed, 17 Nov 2004 19:12:23 -0600, Rick Jones
put finger to keyboard and composed:

Franc Zabkar wrote:

I suggest you identify the vertical output IC or transistor pair. It
should be fairly obvious which IC is the right one by following the
yoke connector to the main PCB. These ICs are usually mounted on a
heatsink and are packaged in SIPs. Their supply is most often derived
from a winding on the flyback transformer. There will be a series
rectifier diode and probably a low ohm fusible resistor.

If you still can't find the vertical IC, post some part numbers and
someone will be able to recognise it. You will most probably find that
the datasheet for the IC will contain an application circuit that will
closely match the layout in your monitor.

OK, here's some info:

The monitor was manufactured by Toshiba; the name is etched into all
of the PCBs. The main board that lays flat across the bottom has what
appears to be P/N PW5253. This has one IC on it - a 42-pin DIP P/N
TA7644. I have tried to find a datasheet for this IC but no luck.
A second small PCB stands at the back of this and has P/N
PWPW5252-3. This board has all of the connectors for RGB, composite
video, split video and mono audio input for the built-in speaker. There
is one IC on this board, P/N TC4053.
The third board is mounted vertically on the right side (facing the
front of the tube). This PCB is P/N PW5252-1. There are 3 ICs on this
board - P/N HD7407, P/N TC4053 and P/N AN5352.
The 4th board in the system is the yoke board, which I guess we're
all pretty sure is no concern with this particular problem. Also, the 3
digital chips - 7407 and 4053 - would not seem to be of concern.
Research on the AN5352 IC showed it to be a character generator, which
seems odd for a monitor. This unit has no capabilities to function as a
terminal AFAIK.

AN5352 = NTE1835
http://www.nteinc.com/specs/1800to1899/NTE1835.html
http://www.nteinc.com/specs/1800to1899/pdf/nte1835.pdf

That leaves the TA7644, which I can find no detailed information on,
just general data that it's a monitor controller IC. Either the vertical
circuit is a part of this 42-pin chip or it's all generated discretely.

TA7644 = NTE1547
http://www.nteinc.com/specs/1500to1599/NTE1547.html
http://www.nteinc.com/specs/1500to1599/pdf/nte1547.pdf

This is the "jungle IC". Follow pin 26 (vertical drive output) to
either a vertical output IC, or to a heatsinked transistor pair.

FYI, you can search for datasheets of equivalent devices at this URL:
http://nte01.nteinc.com/nte/NTExRefSemiProd.nsf/$$Search?OpenForm


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

"Rick Jones" wrote in message
...
Franc Zabkar wrote:

I suggest you identify the vertical output IC or transistor pair. It
should be fairly obvious which IC is the right one by following the
yoke connector to the main PCB. These ICs are usually mounted on a
heatsink and are packaged in SIPs. Their supply is most often derived
from a winding on the flyback transformer. There will be a series
rectifier diode and probably a low ohm fusible resistor.

If you still can't find the vertical IC, post some part numbers and
someone will be able to recognise it. You will most probably find that
the datasheet for the IC will contain an application circuit that will
closely match the layout in your monitor.

OK, here's some info:

The monitor was manufactured by Toshiba; the name is etched into all
of the PCBs. The main board that lays flat across the bottom has what
appears to be P/N PW5253. This has one IC on it - a 42-pin DIP P/N
TA7644. I have tried to find a datasheet for this IC but no luck.
A second small PCB stands at the back of this and has P/N
PWPW5252-3. This board has all of the connectors for RGB, composite
video, split video and mono audio input for the built-in speaker. There
is one IC on this board, P/N TC4053.
The third board is mounted vertically on the right side (facing the
front of the tube). This PCB is P/N PW5252-1. There are 3 ICs on this
board - P/N HD7407, P/N TC4053 and P/N AN5352.
The 4th board in the system is the yoke board, which I guess we're
all pretty sure is no concern with this particular problem. Also, the 3
digital chips - 7407 and 4053 - would not seem to be of concern.
Research on the AN5352 IC showed it to be a character generator, which
seems odd for a monitor. This unit has no capabilities to function as a
terminal AFAIK.
That leaves the TA7644, which I can find no detailed information on,
just general data that it's a monitor controller IC. Either the vertical
circuit is a part of this 42-pin chip or it's all generated discretely.

-


It's unlikely any of this stuff is the vertical output, it'll be either a
6-12 pin IC standing vertically screwed to a heatsink, or a pair of TO-220
or similar cased power transistors on heatsinks.

I'm looking for a schematic for the above named monitor. My vertical
has compressed down to a thin line across the center of the screen.
Replacing the electrolytic capacitors has not helped.
Searches of the web have been fruitless. One monitor schematic for
the Commodore A2002 was alleged to be similar but when I get down to the
component level they are very different.

Rick,
Let me know if you ever find a schematic. You likely came across my site
looking for that diagram and I've never found one either. The 1080 was the
same as the 1902 (non-A version) or so I was told. Anyway, take a look at
the different 1084 schematics. One of them may be similar enough in the
vertical circuit at least to get you going. If you can find a the same IC
used, you're close. It's likely to be the 300 series board location (ie the
vertical output IC will be marked I301). If so, all the components will have
a 3xx number: R301, C301, etc. If you can't find a print, that may help
find your way around. Once you find the vertical IC (resolder it, of course)
check for B+. If it has none, check backwards for a missing source from the
flyback (shorted diode, open fuse/resistor, etc.). Don't overlook a bad yoke
connection.
Commodore monitors are infamous for bad solder connections. When I get
one on the bench, no matter what the symptoms are, I first resolder all the
connections to the flyback and H driver transformer, all diodes and power
transistors and all resistors of 1 Watt and higher, and any other connections
that look "flaky". Then I go for other problems if there are any.

Ray
--

My return addy is spamblocked. To reply, remove the zeroes.

Rick Jones wrote:
I'm looking for a schematic for the above named monitor. My vertical
has compressed down to a thin line across the center of the screen.
Replacing the electrolytic capacitors has not helped.
Searches of the web have been fruitless. One monitor schematic for
the Commodore A2002 was alleged to be similar but when I get down to the
component level they are very different.

Rick,
You're quite correct about the A2002 schematic. I have both
monitors but no schematic for the 1080, unfortunately. However, I did
some digging inside my 1080 and the following info may help. This is now
on my site with a correction regarding the (dis)similiarity between
models. Sorry for the confusion.

It was made by Toshiba and
is unlike any other CBM monitor and my other schematics will not substitute.
Note that it is nearly identical in outward appearance and features to Commodore
monitor models 1902 (non-A model) and 1084. However, the internal construction,
components and board numbers are completely different. I own a 1080, and I have
collected some information about it to assist those who might have to repair
one. The chassis number of my monitor is TAK8520. Although the construction of
this monitor makes troubleshooting difficult because of crowded boards, all
boards are silkscreened on both sides with component identifier numbers. All
internal controls are marked as well.
Note that each section of the monitor is numbered, and that can be used to
locate components in each circuit. The following is viewed facing the rear of
the monitor with the back cover removed. The bottom main PC board contains the
Horizontal Sweep, HV, Vertical and low voltage power supply circuits. The PC
board designation for the H sweep section is 400 (example: H output transistor
is Q404). The vertical sweep section is designated 300. The power supply is 800.
The left upright mounted PC board is analog video and digital signal
processing (100) and an audio amplifier (600). That board swings away to the
left (remove two screws) for better access to it and the bottom board.
The rear upright PC board is an A/V and RGB connector interface and has
both 100 (signal) and 600 (audio) components on it.
Lastly, the CRT board (500) mounted on the back of the picture tube
contains the driver and output transistors for the CRT.

The Low Voltage Power Supply (LVPS): main switcher transistor is Q801, a
2SD1432. The line fuse is a 3 Amp F801, and the B+ fuse is a 1.2 Amp F802.
Both fuses are on the bottom PC board in fuse clips.

HV & Horiz Sweep: the Horizontal Output (Line Output) transistor is a 2SD1427 Q404
and the flyback (line output transformer) T461 is part number TFB5017AD (which
looks like a Panasonic number).

Vertical circuit: this monitor uses descrete components (no ICs). The output
transistors are Q304 2SC2073 and Q305 2SA940. Note that this monitor has a
service switch in the center of the bottom board towards the left side. That
switch should be in the NORMAL position. If in SERVICE, the vertical sweep
will collapse to a single horizontal line (used for CRT setup adjustments).

Ray

Ray Carlsen wrote:

It was made by Toshiba and is unlike any other CBM monitor and my
other schematics will not substitute. Note that it is nearly identical
in outward appearance and features to Commodore
monitor models 1902 (non-A model) and 1084. However, the internal
construction, components and board numbers are completely different. I
own a 1080, and I have collected some information about it to assist
those who might have to repair one. The chassis number of my monitor
is TAK8520. Although the construction of
this monitor makes troubleshooting difficult because of crowded
boards, all boards are silkscreened on both sides with component
identifier numbers. All internal controls are marked as well.
Note that each section of the monitor is numbered, and that can be
used to locate components in each circuit. The following is viewed
facing the rear of the monitor with the back cover removed. The bottom
main PC board contains the Horizontal Sweep, HV, Vertical and low
voltage power supply circuits. The PC board designation for the H
sweep section is 400 (example: H output transistor is Q404). The
vertical sweep section is designated 300. The power supply is 800.
The left upright mounted PC board is analog video and digital
signal processing (100) and an audio amplifier (600). That board
swings away to the left (remove two screws) for better access to it
and the bottom board. The rear upright PC board is an A/V and RGB
connector interface and has both 100 (signal) and 600 (audio)
components on it.
Lastly, the CRT board (500) mounted on the back of the picture
tube contains the driver and output transistors for the CRT.
The Low Voltage Power Supply (LVPS): main switcher transistor is Q801,
a 2SD1432. The line fuse is a 3 Amp F801, and the B+ fuse is a 1.2 Amp
F802. Both fuses are on the bottom PC board in fuse clips.

HV & Horiz Sweep: the Horizontal Output (Line Output) transistor is a
2SD1427 Q404
and the flyback (line output transformer) T461 is part number
TFB5017AD (which looks like a Panasonic number).
Vertical circuit: this monitor uses descrete components (no ICs). The
output transistors are Q304 2SC2073 and Q305 2SA940. Note that this
monitor has a service switch in the center of the bottom board towards
the left side. That
switch should be in the NORMAL position. If in SERVICE, the vertical
sweep
will collapse to a single horizontal line (used for CRT setup
adjustments).

Thanks Ray. The monitor is underneath my bench at work and I'm off
until the Monday after Thanksgiving so I won't get to delve into it
again until then. Maybe with this info and the datasheet for the NTE
equivalent of the big TA7644 IC I can troubleshoot the problem.

--

Rick Jones
Remove the Extra Dot to e-mail me

How come we choose from just two people for President and fifty
for Miss America?